Reduced complexity channel estimation for wireless communication systems
First Claim
1. A method for deriving an estimate of a wireless channel in a wireless communication system, comprising:
- obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one;
obtaining an intermediate matrix for the DFT matrix; and
deriving a second channel estimate based on the intermediate vector and the intermediate matrix.
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Abstract
Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector {circumflex over (H)} for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix {tilde over (W)}, where K>1. An intermediate matrix A for the DFT matrix {tilde over (W)} is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vector B and the intermediate matrix A. In one implementation, the intermediate vector B is obtained by first computing DFTs of a matrix ĤT×L, which is formed based on the vector {circumflex over (H)}, to provide a matrix GL×L. Inner products between the columns of a base DFT sub-matrix W1 and the rows of the matrix GL×L are then computed to obtain the entries of the intermediate vector B.
40 Citations
24 Claims
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1. A method for deriving an estimate of a wireless channel in a wireless communication system, comprising:
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obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one; obtaining an intermediate matrix for the DFT matrix; and deriving a second channel estimate based on the intermediate vector and the intermediate matrix. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for deriving a channel estimate in a wireless communication system, comprising:
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obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and K discrete Fourier transform (DFT) sub-matrices of a DFT matrix, where K is an integer greater than one; obtaining an intermediate matrix derived based on the K DFT sub-matrices; and deriving a second channel estimate based on the intermediate vector and the intermediate matrix.
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16. A method for deriving an estimate of a wireless channel in an orthogonal frequency division multiplexing (OFDM) communication system, comprising:
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forming a first matrix for an initial frequency response estimate of the wireless channel; computing discrete Fourier transforms (DFTs) of the first matrix to obtain a second matrix; computing inner products between a base DFT sub-matrix and the second matrix to obtain an intermediate vector; obtaining an intermediate matrix derived for a DFT matrix for the initial frequency response estimate; and deriving a channel impulse response estimate based on the intermediate vector and the intermediate matrix. - View Dependent Claims (17)
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18. A memory communicatively coupled to a digital signal processing device (DSPD) capable of interpreting digital information to:
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obtain an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one; obtain an intermediate matrix for the DFT matrix; and derive a second channel estimate based on the intermediate vector and the intermediate matrix.
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19. An apparatus operable to derive an estimate of a wireless channel, comprising:
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means for obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one; means for obtaining an intermediate matrix for the DFT matrix; and means for deriving a second channel estimate based on the intermediate vector and the intermediate matrix. - View Dependent Claims (20, 21)
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22. A device in a wireless communication system, comprising:
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a demodulator operative to receive a pilot transmission on a group of designated subbands; and a processor operative to obtain a first channel estimate for the group of designated subbands based on the received pilot transmission, obtain an intermediate vector derived based on K sub-vectors of a vector for the first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one, obtain an intermediate matrix for the DFT matrix, and derive a second channel estimate based on the intermediate vector and the intermediate matrix. - View Dependent Claims (23, 24)
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Specification